<!--
 * @Description:++前置和后置
 * @Author: Sun
 * @Date: 2019-07-01 20:05:50
 * @LastEditors: Sun
 * @LastEditTime: 2019-07-13 22:44:13
 -->
<!DOCTYPE html>
<html lang="en">

<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>++前置和后置</title>
	
	<script>
		window.onload = function () {
		  //  let m=1;
			//  let p=1;
			//  console.log("m",m++)
			//  console.log("m2",m)
			//  console.log("p",++p)
			var a=10,b=20,c=30;
			++a; //11
			a++;//12 13  21    30  13
		  let e=++a+(++b)+(c++)+a++
			console.log(e)

		}
	</script>
</head>

<body>
  <div>
		 A++ ++后置 先运算后自加 <br>
		 ++A ++前置 先运算后自加<br>
		 onfocus 获取焦点 <br>
		 onblur 失去焦点 <br>
	</div>
</body>

</html>